X-ray apparatus



May 5,4 l1942.

e. FRANK '2,231,931

x-RAYAPPARATUs Filed June 27, 193s 5 sheetsfsheet '1'.

May 5, 1942*-` G. FRANK x-nAYAPrARATus Filed'June 27, 1959 5Sheets-Sheet 2 May 5, 1942. G. FRANK 2,281,931

' X-RAYE'APPARATUS l Filed June 27, 1939 5 Sheets-Sheet 5 May 5, 1942.ca. FRANK X-RAY APPARATUS yFiled June'z'r, 1959 5 sheets-sheet 4 May 5,1942; l G, FRANK 2,281,931

x-RAY'ArPARATus Filed June 27. l1959 s "sheets-sheet 5 iff GAE/HEL 1Ffm/wr Patented May 5, 1942 X-RAY APPARATUS Gabriel Frank, Budapes mesneassignments, to and Trust Company, Hartford, Conn.,

Hartford National Bank Hungary, assigner, by

as trustee Application June 27, 1939, Serial No. 281,467 In Germany June27, 1938 15 claims. (o1. 25o-61.5)

My invention relates to a method and apparatus for representingcross-sections of bodies by means of X-rays.

As is well known, radioscopy or radiography is based on the fact thatinside the body subjected to radioscopy many parts have a greater orless absorption for X-rays. As a result a shadow image of the partcapable of absorption which is inside the body was obtained. It is,however, also possible that small details are absorbed in the shadow ofthe part that is in front or at the back of the part and as a resultthese details become invisible. The X-ray image is simply a largequantity of superposed shadow images and it is often very diilicult,even for a professional observer, to properly interpret the same.Several methods have been proposed for taking more exact X-ray picturesin such manner that the desired cross-section of the body to be examinedis obtained without its purity being aiected by the shadows of the partslocated in front or at the back thereof, but in general such methodshave numerous disadvantages.

According to one of these methods, an X-ray tube and a light-sensitivemember are moved about an axis within the plane of the section desiredso that the focus of the tube, the axis of rotationy and a given pointof the light sensitive member are always located on a straight line. Inthis manner it would be possible to ensure that the parts nearer to theaxis appear to be more clearly dened, and those parts more distant fromthe axis are faded. However, such a method only enables one to makepictures of longitudinal section-planes and it is not possible to makepictures of transversely located bodystrata of elongated bodies.Furthermore, the faded shadows of the parts located in front of and atthe backof the section-plane to be represented interfere with the image.

The main object of my invention is to provide an improved method oftaking X-ray pictures of a body-section.

Another object of my invention is to provide an optical system for usein reproducing pictures of body-sections.

A still further object of my invention is to produce a large number ofpartial X-ray exposures which, when projected one upon the other, form acomposite picture of a body-section.

Further objects and advantages of my invention will appear as thedescription progresses.

My invention is based on the recognition of the fact that all raysemerging from the body and received from a focus located in the plane ofthe cross-section and illuminating body from innitely many sides,jointly determine the crosssection.

In accordance with the invention I take several partial radiographs ofthe section with a narrow beam of X-rays, enlarge the partialradiographs in a direction perpendicular to the plane of the section,and superpose the enlarged radiographs with mutual angulardisplacements.

In order that the invention may be clearly understood and readilycarried into eiiect I shall describe the same in more detail withreference to the accompanying drawings in which;

Figure 1 is a diagrammatic perspective view of `an arrangement for usein explaining the theory of the invention,

Figure 2 is a sectional view along line 2-2 of Fig. 1,

Figure 3 is a view of a portion of Fig. 2 with several members thereofin different positions,

Figures 4, 4a, 4b, 5, 5a and 5b are plan views of reproductions ofvarious cross-sections,

Figure 6 is a diagrammatic perspective view of a device for recordingthe line images on a `,photographic lm,

Figures l and 8 are diagrammatic perspective views of devices forenlarging and superposing the partial images,

`Figure 9 is a side view in perspective of a device embodying theinvention,

Figure l0 is a perspective view of a device for carrying out the methodaccording to the invention,

Figures 11 and 12" are plan views of partial images obtained with thedevice of Fig. 10.

Figure 13 is a sectional sectional side view of a device for moving thelight-sensitive member, and

Figure 14 is a sectional view along line I4-I4 of Fig. 13.

Figure 15 is a perspective View of a device embodying the invention inwhich a lm band is used for recording the partial pictures.

Figures 16 and 17 show another modification of a device according to theinvention.

Figure 18 is a diagrammatic side-view of a device which operates on thesame principle as that shown in Fig. 6, but with cinematic reversal ofthe motion.

In Fig. 1 a body I, of which a cross section 50 is to be reproduced,comprises an annular portion 3 of semi-transparent material such asmuscle tissue of a human leg, and a core portion 4 of a material whichis less transparent to X-rays, such as a bone. `A beam of parallelX-rays I0 emanating from a remote source (not shown) passes through bodyI, and a narrow X-ray beam having a band-shaped cross-section passesthrough a narrow elongated slot I in a diaphragm 5, for example of lead.The directions of the X-rays and the slot 5l determine the plane of thecross-section 50 (indicated by cross-sectioning). The X-ray beam passingthrough the slot 5I produces a narrow image 8 on a light-sensitivemember 1, i. e., an X-raysensitive plate, and the density of this imagecorresponds to the different degrees of absorption l of the X-rays bythe portions 3 and 8l of the body I at section 50. Of course thediaphragm 5 might also be placed between the object and the source ofX-rays, but with the situation shown in the drawing a narrower beam ofX- rays may be produced.

If we assume that the line-shaped image Bis enlarged in the direction ofthe double-headed arrow 52 over an entire circular area 55 we wouldobtain a picture such as indicated by reference numeral 9 in Fig. 2. Itshould be noted in Fig. 2 that the image enlarged in the direction ofthe arrows 52 is shown rotated about the axis 8 of Fig. 1 so as to liein the plane of Fig, 2. Y

As will be pointed out hereinafter, this enlargement of the image, whichmust be at least as long as the length of the line-shaped image of thesection projected from a direction normal to the first one, may beobtained by optical means or by a displacement of the image carrier orlight-sensitive member itself.

If, as illustrated by Fig. 3, the source of the .-rays is rotatedjointly with diaphragm 5 :and the X-ray sensitive plate 'I relative tothe body I through an angle a about the axis 54 of Fig. 1, which axis isnormal to the plane of section 58 and intersects this plane at a pointII, a second partial image may be produced. The point of intersection IIwill be referred to as the point of rotation. Assuming that this secondpartial image produced on plate I is also enlarged in a lateraldirection so as to extend over the whole of the circular area 55, asuper-position of the two partial pictures is produced, as indicated byreference numeral 56 in Fig; 3, whereby the rst and second partial imageare assumed to be mutually rotated through the same angle. In Figure 3the plate 55 is shown rotated into the plane of section 5!) and thedifference in density of the two partial images 9 and 56 arecross-sectioning of different spacings.

Several partial pictures may be made in this manner and the enlargedpictures turned over into the plane of section 5i) and superposed withmutual rotations about theimage-point 5'I of the point of rotation IIyequal to the corresponding rotations of the bdy I relatively to thesource of X-rays, diaphragm 5 and plate l. If the several rotationstogether amount to 180, the superimposed pictures will represent anexact image of the section 5t. The larger the number of partial images,the better will be the total image.

The rotation and exposure may also be made continuously through an angleof 180 so that the total image is a continuous integration and not astep by step superposition.

The cross-section of the core 4, no matter yfrom what side it isexposed, is only slightly transparent to X-rays, and therefore thecentral part of the X-ray sensitive plate 'I receives only very smallquantities of radiation and remains blank. On the other hand a portionof the plate surrounding this blank central portion Will beblackindicated byk ened to a certain degree, and the portion of theplate surrounding this second portion wiil be blackened still moreintensely.

Figs. fi, fia, lilo, 5, 5a and 5h sh w the reproduction of variousidealized cross-sections for eX- ample, skuil and arnibone. En Fig. iathe reference numeral l2 designates the cross-section to bera-diographed, in Fig. 4 reference numeral vIii indicates an extendedand turned-down partial picture the blaclening being represented bycross hatching, and in Fig. lib reference numeral I4 the. resuitobtained by superposition or integration of all the partial pictures i3.

In Fig. 5a, reference numeral i5 designates the cross-section to beradiographed, in Fig. 5, reference numeral it indicates a superpositionof two of the partial pictures and in Fig. 5b reference numeral ilindicates the result ci the superposition of all partial pictures or theintegration of blackening.

As only `the relative movement between the source oi X-rays and theobject is cf interest, the same result is obtained if the object isrotated, while the source of X-rays, the diaphragm and the ray-sensitiveplate are not rotated about the body.

A device in which the obi-ect is not rotated is illustrated in Fig. lain which an object to be photographed E26, shown as the body of apatient. rests upon a piatform E36 which can be raised and lowered bysuitable means (not shown) but which cannot be rotated.

Suspended from the ceiling so as te be rotatable in a horizontal planeis a support IZ'I having two arms t28 and I 2). The support 21 ismounted on a rod it@ and can be rotated by an electric motor E32.

The rod iii@ can be telescoped within a tubular member M5 fastened tothe ceiling. Secured to the end of rod i3@ is a rope E33 which passesover two pulleys and carries a counterweight |34. This allows thesupport mi to be readily moved up and down.

Arm 23 carries an X-ray generating apparatus itl, whereas arm 25 carriesa rotatable drum 38 upon which a ray-sensitive film (not shown) isplaced and a split diaphragm i539. The drum ist' is rotated by means ofmotor |32 and forthis purpose the shaft upon which drum 635 is mountedcarries a gear engaged by a worm gear Ulli mounted on the end of a shaftM2. rEhe other end of shaft carries a gear which engages a gear Mldmounted on the end oi a shaft ld! driven by motor E32.

When the motor i is placed into operation the support itl? rotates tothereby rotate the source of X-rays I3? as well Vas the drum I38 anddiaphragm it@ about the axis itil. At the same time the drum i with theX-ray sensitive film thereon is rotated about the horizontal axis of thedrum.

A simple method of recording the line images on a photographic film willbe described with reference to Figs. 6, '7 and 8. Referring to Fig. 6,assume that body l, and consequently also the section 5t thereof, arerotated about an axis 511 normal to the plane of section ii@ at 'thepoint of rotation Ii. A drum consisting of X-ray impervious material orlined with such a material carries an X-ray-sensitive film 'e secured toits peripheral surface and is arranged at the rear of diaphragm 5 withits anis 23 in the plane of section iti and slot di. The point of thepoint of rotation Il `on the periphery of drum 22 is designated in Fig.6 by reference numeral I8.

The drum is rotated about axis 23 and body I is rotated about axis 54with the same angular speeds and due to these continuous rotations thepartial images of cross-section 50 are recorded side by side on the lm 6to form a composite image, containing every detail of cross-section I5.However, the true form of the cross-section cannot be directly perceivedfrom the record so formed. To obtain this I use an arrangement such asshown in Fig. 7.

In Fig. 7 the reference numeral I9 designates a rotatable drum oftransparent material, such as glass, carrying the developed iilm 6produced in Fig. 6. The drum |9 has exactly the same outer diameter asdrum 22 of Fig. 6 and is rotated about its axis 29. A diaphragm 2|provided with a slot 24 is identical with the diaphragm 5 and isarranged parallel to the axis with the slot 24 in a plane passingthrough axis 20 perpendicularly to the diaphragm 2|.

Arranged within the center of drum I9 is a punctiiorm light source 25 bywhich the diaphragm 2| is illuminated through the lm 6.

A narrow beam of light passes through slot 24 and is optically analogousto the beam of X-rays emerging from the diaphragm 5 in Fig. 6 Thisnarrow beam of light is enlarged in a direction perpendicular to theplane of axis 2|] and slot 24 by being passed through two cylindricallenses 25 and 2l'. As a result an enlarged picture 53, similar to thevpicture 9 of Fig. 2, is projected on a projection screen 28. Screen 28is in the form of a photographic plate which is caused to rotate with aconstant angular speed about an axis 2.9 passing through the image pointI8 of the point of rotation and a slot 24. The plate 28 is rotated withexactly the same angular speed as that of drum I9 by suitable drivingmeans (not shown). The effect of this rotation is geometricallyidentical with the eiIect shown in Figs. 3, 4 and 5 and exists in anintegration of the blackening effects in each position of the plate 21%and drum I9, so that the desired reproduction of section 50 is obtainedon plate 28 after it is developed.

It should be noted that the ratio between the radius of drum I9 and thedistance between the record iilm 6 and plate 28 should not be excessivein order that undue magniiication will not occur and films of normalsize may be used. For this reason, it may be advantageous to use,instead of a drum with a light source at its center, any other type offilm transporting device that permits the light source to be placed at agreater distance from the record lm.

It is also possible to dispense with the second photographic film 28 andto make the desired picture of the cross-section 50 directly visible andsuch an arrangement is schematically illustrated in Fig. 8. In Fig. 8,in which the same reference numerals are used for the parts of Fig. 7,the enlarged image produced by lenses 2B and 2l is not directlyprojected upon a screen, but is first rotated about the axis ofprojection by a lens or kaleidoscopic mirror system 35 which is rotatedat the same angular speed as drum i9. The beam of light subject to therotation by the system 35 is thrown on a viewing screen 3U, on which animage 31 becomes visible. The speed of rotation is made sufficientlyhigh that the human eye could not perceive the rotation of the image onscreen 38, but only an impression of the picture of the cross-section.

The required speed of rotation during the X- ray exposure depends on theintensity and the and 89 of a control apparatus 4'|.

-as follows. 'switched-on by a switch 45 the motor starts and 1 latter.

hardness respectively of the X-rays, on the sensitivity of the iilm andon the intensifying screen to be used. Inany case, however, the speed ofrotation of the object about axis 54 (Fig. 6)

- and that of the film carrier about axis 20 (Figs. 7

and 8) should be correlated. The devices for effecting these tworotations are preferably coupled in a constrained manner. Also thedevices for moving the record film and the picture carrier 28 orthe'optical image rotating system 35 in Figs. 7 and 8 may be coupled ina constrained manner, i. e., through suitable gearing.

One suitable method of coupling the iilm drum rotation with the rotationof the object about axis 54 is shown in Fig. 9. In this gure an X- raytube 38 is secured to a suitable support 39 so that it can be adjustedin a vertical direction. A diaphragm 46 provided with a slot 3| and anX-ray impervious lm drum 4| are mounted within a housing E2 so as to bemovable in a vertical direction together with the X-ray tube. Moreparticularly the housing 82 may be mechanically interconnected with theX-ray tube 38 so that both these members can be raised or loweredtogether. The object to be exposed (not shown) is placed on a supportingdevice comprising a disc 42 adapted to be rotated in a hori- Zontalplane. The disc 42 carries two vertical supports provided with two belts43 for holding the object. Disc 42 and drum 4I are rotated by anelectric motor 44 and are mutually coupled in a constrained. manner.More particularly, drum 4| carries a worm-gear 32 driven by a Worm 33mounted on a driving shaft 34 which is driven through a pair of bevelgears 36 from shaft 59 of motor 44. Shaft 58 also carries a worm 59which drives a worm-wheel 60 secured to disc 42.

Disc 42 has a stud 6i, co-operating with a switch device 86. This switchdevice has a press button 8| and is of the known type that closes aContact when being pushed once and breaks the v contact when then beingpushed again. By wires 86 the -switch device is connected to terminals8B The control apparatus is connected to the transformer 9| of the X-raytube 39 by a cable 90.

The operation of the arrangement described is When the current of motor44 is both the disc 42 and the drum 4| begin to rotate. When disc 42carrying the object to be photographed has moved some time, stud 6|comes into Ytouch with button 8| and pushes the The energizing currentfor transformer 9| is thereby caused to flow and the exposure is made.

Meantimes disc 42 and drum 4I continue their rotation and when disc 42has rotated over 360, notch 6| again pushes button 8| and the current oftransformer 9| is switched-off.

In some cases, for example 'for locating a tumor, it may be desirablethat a plurality of cross-sections arranged with small mutual distancesshould be reproduced in rapid succession. For this purpose anarrangement such as shown in Fig. 9 with slight alterations may be used.More particularly, the rotating cylindrical iilm drum 4! may bereplacedby a continuous filmband. The patient standing on the rotarydisc 42 is turned several times while simultaneously the disc is movedupwards or downwards. A slowly rising screw'surface is then described bythe X-rays relatively to the object. The iilmband is caused to move infront of the diaphragm at a uniform speed.

An arrangement with which the latter method can be carried out is shownschematically in Fig. 15. The object body (not shown) is positioned ondisc 42 and fixed thereto by means of belts 43. Disc 42 is rotated bymotor 44 as described with relation to Fig. 9, with the difference, thatdisc 42 is mounted on a square shaft |02 and that the worm-Wheel 60 isnot secured to disc 42, but rotatably mounted on a certain support notshown. Disc 42 has a square central aperture in which fits the shaft|02, so that the latter may slide upwards and downwards in theworm-wheel 60, but is caused to rotate if the Worm-wheel rotates. Thelower end |03 of the shaft has a circular section and is threaded. It isscrewed into a base |04. Thus when the Wormwheel 60 is rotated byelectromotcr 44 the shaft |02 and disc 42 are also rotated but at thesame time are screwed upwards or downwards according to the sense ofrotation.

Instead of a drum carrying an X-ray sensitive film, laid around thecylindrical surface of the drum as in Fig. 6, there is provided in Fig.a filmband |05, transported by means of a drum |66 provided withsprockets |01 and |08, which engage perforations |09 and ||0 of the film|05. The drum |06 is rotated by motor 44 in the same manner as drum 4|in Fig. 9. When the radiograph so obtained is viewed by means of anarrangement as shown in Fig. 8 and the optical system 35 is rotated soquickly that one revolution thereof corresponds to one revolution of therotary disc, the observer sees a picture of a continuously falling orrising cross-section.

Obviously, the rotation of the rotary disc must be a slow one, a singlerotation requiring at least from 4 to 5 seconds.

Instead of rst making a record of the lineshaped images 8 (Fig. 1) andafterwards enlarging the same by optical means, the enlarged partialimages can also be made directly on the rst film and such a method willbe described in connection with Figures 10` to 14.

Referring to Fig. 10, a drum 62 impervious to X-rays carries on itsperipheral surface an X-ray sensitive lm 63. The axis of drum 62 lies inthe plane of the section to be reproduced and when the drum isstationary, a line-shaped image is obtained corresponding to thecross-section 50, as shown in Fig. 1. If drum 62 is rotated there willbe produced on film 63 after one complete revolution an enlarged imagewhich, after development of the lm, would appear as shown in Fig. l1.Assuming that the body is rotated through an angle a about axis 54 andthat the lm 63 is rotated through the same angle a about an axis normalto the axis of cylinder 62 and passing through the image I8 of the pointof rotation H, there will be produced, after a second completerevolution of the drum 62 a second partial picture superposed on thefirst picture with a mutual rotative displacement through angle a. Theresulting composite image is shown in Fig. l2.

The circular photographic film 63 is carried by a disc 64 of a flexibleand elastic material, for instance steel which is retained at thecylindrical surface of drum 62 by a guide 65 so that it can be rotatedwhile preserving its cylindrical form.

By rotating the plate 64 through an angle a after each completerevolution of drum 62 and continuing this stepwise rotation until thefilm nas been rotated through at least 180, a superposition of partialimages is obtained representing the cross-section 50 to be examined.

The diameter of disc 64 is preferably made only slightly less than thatof drum 62 so that tti-ile; opposite points of the plate nearly reacheach o er.

It is not necessary that disc 64 moves step by step, but its rotationmay be continuous provided that it is in synchronism with the rotationof the object relatively to the X-rays I0 and diaphragm 5. The number ofrevolutions of drum 62 must be much greater, for example 200 timesgreater, `than that of the synchronous rotation of the disc 64.

A device in which the correlation of the rotation of the plate 64 andthe drum 62 is effected is shown in Figs. 13 and 14. As shown in thesefigures, a shaft 68 is keyed to drum 62 and is rotatably supported on abearing 6l. The shaft 68 is driven by a belt |49 from an electric motor|50 so as to rotate the drum. The other end of drum 62 is rotatablymounted on a stationary Shaft 69 which is keyed to a second bearing |00.Fixedly secured to the free end of shaft 69 is a Worm 'l0 which engagesa worm-gear 1| which is secured to a gear T2. Gears 'H and 'I2 arerotatably mounted on a support |0| secured to drum 62. Rotatablysupported' by drum 62 is a shaft 66 carrying a gear 73 which meshes withgear 12. The disc 64 is fixedly secured at its center I8 to the free endof shaft 66.

When drum 62 is rotated about shaft 6,9, Wormgear 1| is rotated due toits being in engagement with the worm 'i0 and as a result the disc 64 isrotated. Thus the rotative motion of drum 62 is, with a certaingear-ratio (for example 1:200), transmitted to disc 64 and to thephotographic film 63 carried thereby.

In Figs. 16 and 17 an object person |21 is standing on a rotating tablewhich is rotated by a motor ||2 by means of driving shafts H3 and H4,mutually coupled by a pair of bevel gears H5. The top of table isprovided with a groove H6. A leaning disc H7 is rotatably mounted aboutan axis |8. A rope drive system is provided for driving disc from theturn table l. The rope i I9 runs in the groove H6 and over guide idlers|20 and |2| and drives the disc Disc H1 carries an X-ray sensitive film|26. It makes a small angle With the X-rays radiated by the X-ray tube|22. A slot diaphragm is thereby rendered superfluous.

The disc is provided with a stud |23 cooperating with a switch |24 as inthe case of Fig. 9 for switching-on and olf the energizing current ofthe high tension supply transformer |25 for X-ray tube |22, so that theobject and the photographic lm are exposed to the X-rays during one fullrotation of the discs and ||I.

The invention is not only of importance for medical appliances but mayalso be used for industrial purposes such as material-testing.

While I have described my invention in connection with specific examplesand certain details of construction, I do not desire to be limitedthereto as obvious modification will readily present themselves to oneskilled in the art.

What I claim is:

1. A method of reproducing an X-ray image of a section of a body,comprising the steps of passing X-rays through the body in severaldifferent directions from a source of X-rays located at constantdistances from a given point of the section and from a ray-sensitivemember, confining the X-rayspassing from the body to the ray-sensitivemember toa narrow beam lying in the plane oi the section to producenarrow partial images on the member, enlarging theA partial pictures ina direction perpendicular to the plane of the section, and superposingthe enlarging partial pictures` with mutual angular displacementscorresponding to the angles between the directions of the X-raysstrikingthe body.

2. In producing upon a ray-sensltive member a true X-ray image of asection of a body, the steps of exposing the body to X-rays to cause anarrow beam of X-rays lying on the plane of the section to pass from thebody to the member, and rotating the body about an axis perpendicular tothe plane of the section while moving` the member with the exposedpoints moving in a plane substantially perpendicular to the plane of thesection to thereby produce a plurality of lateral partial images of adisc-shaped portion of said body on said member.

3. A method of producing an image of a section of a body, comprising thesteps of passing X-rays through the body in several diierent directionsfrom a source of X-rays located at constant distances from a given pointof the section and from a ray-sensitive member, confining the X-rayspassing through the body to the X-raysensitive member to a narrow beamlying in the plane oi the section, moving the ray-sensitive member toproduce a plurality of adjacent linear images thereon, developing theray-sensitive member, projecting the linear images one after the otherwhile optically enlarging the same, and superposing the projections ofthe enlarged images with mutual displacements equal to the angles usedbetween the directions of the X-rays to form a true image of thesection.

4. In a method o taking an X-ray picture of a section of a body, thesteps of making a plurality of line-shaped partial exposures with narrowX-ray beams lying in the section and .eX- tending in various directionsand with equal focal distances from a given point of the plane of thesection, and moving a ray-sensitive member relatively to the X-ray beamto record a plurality of adjacent line-shaped partial pictures.

5. In a method of taking an X-ray picture of a section of a body thesteps of making a plurality of line-shaped partial exposures with narrowX-ray beams lying in the section and extending in various directions andwith equal focal distances from a given point of the plane of thesection, and continuously moving a ray-sensitive member relatively tothe X-ray beam torecord a plurality of overlapping line-shaped partialpictures.

6. A method of reproducing a cross-section of a body, comprising thesteps, subjecting the body to X-rays emanating from a source, passingfrom the body to an image carrier a narrow beam of X-rays lying in theplane ofthe section, rotating the source and image carrier relatively tothe body around an axis normal to the plane of the section andsimultaneously rotating the image carrier about an axis normal to thesurface thereof.

7. An apparatus for taking an X-ray picture of a section of a body,comprising a source of X-rays, a ray-sensitive member for receiving thepicture, means for rotating said source and member relatively to saidbody about an axis normal to the section at the point of rotation, andmeans to move said member in its plane and in dependence on the rotarymovement of said source `and member.

8. An apparatus for taking an X-ray picture of a section of a body,comprising a source of X-rays, a ray sensitive member for receiving thepicture, means for rotating said `source and member relatively to saidbody about an axis normal to the section at the point of rotation, andmeans to move said member in its plane and in dependence on the rotarymovement of said source yand member, said latter means comprising a drummounted on an axis lying in the plane of the section, means to rotatethe drum about its axis, a disc of flexible material supporting said raysensitive member and pivoted on said drum at its center, means forholding said disc to the cylindrical surface of the drum, and means forrotating said disc about its center.

9. An apparatus for taking X-ray pictures of a section of a body,comprising means for producing a narrow beam of X-rays lying in theplane of the section including a source of X-rays, an elongated carrierfor receiving images produced by said X-ray beam, means for producing arelative rotation between said body and said source and carrier, andmeans for moving said carrier perpendicular to the plane of the section.

10. An apparatus for reproducing a series of band-shaped picturesconstituted by lateral X-ray images of a disc-shaped portion of a bodytaken in several directions in the plane of the disc-shaped portion,comprising a projection screen, means for individually projecting theimages with a narrow X-ray beam lying in the plane of the section beingviewed, means for enlarging each image in a direction normal to itslength, and means for producing relative rotation between the projectedimages relative to the screen.

11. An apparatus for reproducing a series of band-shaped picturesconstituted by lateral X-ray images of a disc-shaped portion of a bodytaken in several directions in the plane of the disc-shaped portion,comprising a projection screen, means for individually projecting saidimages upon said screen in rapid succession, means for enlarging eachimage in a direction normal to its length, and optical means forrotating the projected beams of light.

12. In an installation for making an X-ray photograph which is a truerepresentation of a section of a body, a drum rotatable about an axislying in the plane of the section, a flexible disc carried by thecylindrical surface of the drum and adapted to receive anX-ray-sensitive layer, a guide holding said disc to said surface, apivot secured to said disc and rotatably supported by said drum, andmeans for rotating said disc about said pivot.

13. In an installation for making an X-ray photograph which is a truerepresentation of a section of a body, a drum mounted on an axis lyingin the plane of the section, means to rotate the drum about its axis, adisc of iiexible material pivoted on said drum at its center, means forholding said disc to the cylindrical surface of the drum, and means forrotating said disc about its center.

14. The method of producing a true X-ray image of a section of a body,comprising the steps of making a large number of lateral X-ray images ofa plate-shaped portion of the body at various angles by a narrow beam ofX-rays lying in the plane of the section being viewed and with such.enlargement as togive eac-h image a Width several times the Width ofthe narrow X-ray beam, and superposing said images with the pointscorresponding to the axis of the Xray beams coinciding and with mutualangular displacement of the images about said points.

15.V The method of producing a, true X-ray image of a section of a body,comprising the steps of making a large number of lateral X-ray imagesof` a plate-shaped portion of the body at l0 various anglesv by-anarrowfbeam of=Xrays lying in the planel of'V the section beingviewedwliile giving each imagea width atJ leastequal tothe length of theimage produced by an X-ray beam whichis normal tothe X-ray'beamproducingthe image,l and'superimposing-A the images with the pointskcorresponding to the axis of the X-ray beams coinciding and with mutualangular displacement of the images aboutsaidpoints.

GABRIEL FRANK.

